Feeding mechanism for sewing machines



Aug. l l, 1925.

S. G. TATE FEEDING MECHANISM FOR SEWING MACHINES Filed Oct. 1.5, 1919 4 Sheets-Sheet l Aug. 11, 1925. 1,548,362

' S. G. TATE FEEDING MECHANISM FOR SEWING MACHINES Filed Oct. 16, 1919 4 Sheets-Sheet 2 attenua S. G. TATE FEEDING MEGHANISM FOR SEWING MACHINES Aug` 1l, 1925.

Filed Oct. 1.5, 1919 4 Sheets-Sheet 5 3 vwe nto/z,

Aug. l l, 1925.

1,548,962 s. G. TATE FEEDING MECHANISM FOR SEWING MACHINES Filedct. 16. 1919 4 sheets-sheet 4 a u n lil, Mafia SAMUEL GEORGE TATE, OF CHICAS-G, LLEN''IS, ASL'GNOR'TO 'UNION SPECAL lltr- GHINE COMPANY, OIF GHIGAG, HQLNQS, A CGREDHATEON @E ILLNOI'S.

rnnnrrre raisonnement For, snwiiie Maestrias.

Application filed October 16, 1919. Serial No. 331,144.

To all whom t may concer/vt:

Be it lrnown that l, SAMUEL Grenen Turn, a citizen of the United States, residing at Chicago, in the county of Goch, State of Illinois, have invented certain new and useful improvements in Feeding Mechanisms for Sewing Machines, of which the following is a description, reference being had to the accompanying drawing, and to the. figures (if-reference marked thereon.

The invention relates to new and useful improvements in feeding mechanisms for sewing machines, and more particularly to a feeding mechanism having main and auxiliary feed dogs which are given a differential movement relative to each other.

An objectof the invention is to provide a differential feeding mechanism wherein an auxiliary feed dog is provided with a controlling mechanism including a shiftahle fulcrum, the extent of movement of which may he varied for varying the feed stroke of the auxiliary feed dog.

A further object of the invention is to provide a feeding mechanism of the alcove character' wherein the auxiliary feed dog is pivotally mounted on the feed loar which carries the main feed dog and receives all its i'novements from said feed loar.

.il still further object of the invention is to provide a sewing machine having a relatively small work supporting arm with a main feed dog and an auxiliary feed dog disposed at the free'end thereof and wherein said feed dogs are mounted on a single feed har extending lengthwise of the arm and fori;A the sole driving connection for the feed dogs, and wherein a controlling` mechanism is associated with the auxiliary feed 'dog for modifying the extent of movement imparted to the auxiliary feed dog by the feed bai'.

These and other objects will in part loe obvious and will in part he hereinafter more fully disclosed.

ln the drawings, which show by way of illustration one embodiment of the invention' F ,ire l is a longitudinal sectional view through a worlr supporting arm having` my in'iprovefl feeding mecl-ianism applied thereto;

Fig. 2 is a view. partly in plan and partly in, horizontal section, of the sarne i Fig. 3 is a sectional view taken on the line 3-3 of Fig. l;

Fig. l is a sectional view taken on the line 4. l of Fig. l;

Fig. 5 is a perspective view of the main feed dog;

Fig. 6 a side view of the auxiliary feed dog;

Fig. 7 is a plan view ofthe auxiliary feed dos;

Fig. 8 is a rear view of the auxiliary feed dos;

F ig. 9 is a detail vier:l showing in side elevation the feed har, the feed dogs, and the operating devices therefor, said feed dogs being on their return stroke and showing in dotted lines the dogs at the end of the rearward stroke;

l() is a view similar to Fig. 9, lout showing the feed dogs on their forward strolre and in dotted lines the extreme forward end of their stroke;

Fig. 11 is a diagrammatic view showing the movements of the main feed dog and the movements of the auxiliary feed dog 'and the arrangement of the parts which give to the auxiliary feed idog a differential movement; and

l2 is a sectional view taken on the line -a" of Fig. 1.

The invention is directed broadly to a feeding mechanism for sewing machines .having a feed har on which a main feed dog is rigidly mounted and on which an auxiliary feed dog is pivotally mounted so that it may he given a feed travel equal to or greater than the feed travel of the main feed dog. The invention is particularly adapted to a machine of the type wherein the material heing stitched is tubular in form and is supported by a suspended arm and during the stitching operation is fed off from the end of the arm.

lt is the purpose of this invention to provide a differential feeding mechanism which may be placed in a small compass so that the arm in which it is placed may he made relatively small, and also to provide a feeding mechanism wherein the main feed dog and the auxiliary feed dog derive all of their movements from a single driving connection which extends lengthwise of the arm. To this end, the main and the auxiliary feed dogs are mounted on the feed har, as alcovenoted, and both of these feed dogs are disposed at the free end of the feed bar. The feed bar is moved endwise and is raised and lowered. The movements imparted to the auxiliary feed dog by the feed bar are modified by controlling devices which are connected to the feed bar near the free end thereof.

Referring more in detail to the drawings, which show one embodiment of the invention, the main feed dog is illustrated at 1a and the auxiliary feed dog at 2a. These feed dogs are carried in the forward end of a feed bar 3a. The feed bar 3a is pivotally connected at 4a to a forked arm 5. The bar lies between the forked portions of the arm and a pivot bolt passes therethrough uniting this forked arm to the feed bar. This forked arm is mounted to swing upon an eccentric 6 which is fixed to av shaft 7. The shaft 7 is mounted in suitable bearings in the arm 8 of the machine and is provided with a suitable slot at one end thereof whereby it may be rotated. A set-screw 9 holds the shaft in an adjusted position. By rotating the shaft, the eccentric 6 will be shifted and thus the feed bar 3 will be raised and lowered to bring it into proper cooperation with the fabric.

The main feed dog is provided with fabric engaging teeth 10 and with a shank 11 which fits in a suitable recess in the feed bar 3a and is secured therein by screws passing through slots 12. The auxiliary feed dogl 2a is provided with fabric engaging teeth 13, see Figs. 6 to 8, inclusive. Said auxiliary feed dog also has depending arms 14 and 15. These arms are formed with alined openings adapted to receive a screw 16, see Fig. 1, which passes throughthe feed bar so that the auxiliary feed dog is supported by the feed bar but is pivotally supported thereby so that said auxiliary feed dog may swing upon the feed bar.

The arm 15 of the auxiliary feed dog extends downwardly below the pivot and is formed with an opening 17. A link 18 is pivotally'connected to the arm 15 by a screw 19 which is threaded into the opening 17. The screw becomes the fulcrum for the auxiliary feed dog and will hereinafter be referred to as the fulcrum 19 for said auxiliary feed dog. A segment arm 2O is mounted to rock on a shaft 21 which is fixed in suitable bearings in the work arm 8 by means of a set-screw 22, see Fig. 4. This segment arm is formed withv a segmental slot 23. A link 24 is pivoted at 25 to the feed bar 3El and is pivoted at 26 t'o the segment arm 20. A shoe 28 is mounted so as to slide freely in the slot 23. A bolt 29 passes through said shoe 28 and is held therein by a screw 30 which threads into the end thereof. Said bolt 29 has a threaded opening 33 formed therein. The shoe 28 has a reduced section 32 which receives the end of the link 18, the end of the link thus being held between the segment arm 2O and the head of the screw 30.

From the above, it will be apparent that l have provided a controlling mechanism for the auxiliary feed dog which serves to shift the. fulcrum of the auxiliary feed dog, and it is this shifting of the fulcrum of the auxiliary feed dog that modifies the extent of movement imparted to the auxiliary feed dog by the feed bar. rlhis controlling mechanism is all disposed adjacent the end of the work supporting arm and the movements imparted thereto for shifting the fulcrum are derived from the feed bar.

The extent of movement imparted to the shoe 28 may be varied by shifting the same in the segmental slot 23. prefer to accomplish this by means of an adjusting screw 31 which engages a threaded opening 33 in the head of the bolt 29. The upper end of this threaded screw 31 is formed with a balled head 34 which has a suitable slot for receiving a screw-driver. rllhe balled head 34 sets in a suitable ball socket in the upper face of the segment arm 20 and acap plate 35 also having a ball socket and secured to the segment arm by screws 36 overlies the balled head on the screw 31 and keeps the same from endwisc movement, although said balled head and socket connection permits the screw to shift and permit the shoe 28 to follow the segmental slot 23. By turning this screw 31, the point of connection between the link 18 and the segment arm 2O may be positively shifted and held in an adjusted position.

The feed bar 3n is moved endwise by a lever which is pivotally connected at 38 to a second lever 39. The lever 39 is fulcrumed at 40 to the work arm 8. The lever 39 has a fork 41 at its upper end cooperating with an eccentric 41a on the operating shaft 42. The lever 37 cooperates with an eccentric 43 on this same operating shaft 42.

The operation of the feeding mechanism will be made more clear by reference to Figs. 9, 10 and 11. in Fig. 11, the fnlcrum point for the segment arm 2O is indicated at 0. The path of movement of the pivotal connection between the link 18 and the segment arm 2O is indicated at 0:-a1. rlhe path of movement of the pivotal connection between the link 24 and the segment arm 2O is indicated at but. rllhe path of movement of the pivotal connection 25 between the link 24 and t-he feed bar is indicated at 0. The path of movement of a point on the main feed dog is indicated at g; the path of movement of a point on the auxiliary feed dog is indicated at f; the path of movement of the pivotal point 16 connecting the auxiliary feed dog with the feed bar is indicated l 1,5481, eee

at e, and the' path of movement ofthe fulcrum 19' of the auxiliary feed dog is indi cated at al. Similar positions' of these various points are indicated at 1, 2, 3 andi if in this' diagrammatic view.

lhen the feed dogsare'l in the full l'ine position indicated in Figi. 9, they are at the extreme lower position or at the point 4f. As the feed dogs move' fro-nr this full line position to the'dotte'd' line position' indicated in Fig. 9, the feed dogs move to the' points 1 and likewise the other parts' move to the points l. It will be noted that' the' feed bar is moving rearwardly and also movingl upwardly. The points moving along the paths cira and b-) are moving'v downwardly, and as these points are at the` right of the point the lower end of the auxiliary feed' dogfwill move to the right and upwardly, as viewed in Fig. 1l. The pivotal point for the auxiliary feed dog will also move to the right and upwardly by reason of the fact that the feed bar is: moving to the right and upwardly'. The extent of movement of the pivotal connection between the auxiliary feed dog and the feed bar to the right, however, is greater than the extent of movement of the fulcrum of the auxiliary feed dog, indicated at al, and this results in a greater movementto a point in the upper end of the auxiliary feed dog indicated by the path of move"-44 ment f than is imparted to' a' point in the main feed dog, the path-of movement of which is indicated at g. The feed bar then' moves upwardly and forwardly to they full line position indicated in Figi 10, and the points to which reference has been made above all move to the positions indicated vat 2. The feed dogs are now in engagement with the material and are moving it forward.

lt will be noted that the feeding move ment of the upper end of the auxiliary feed dog is greater than the feeding movement of the main feed dog and, therefore, the material will be gathered and thereby prevent any stretching of the material which would otherwise occur when passii'rg under the presser foot. rl`his travel'of the auxiliary dog is due to the fact that the movement of the fulcrum for the lower end of the auxiliary feed dog is' less than the stroke of the main feed dog during this period. The fabric engaging surface of the auxiliary feed dog' is curved about a point coin'- cident with the pivotal connection of the' auxiliary feed dog to the feed bar, and a line passing through the extreme upper points of the: fabric engaging teeth of the main feed dog is substantially tangential toz the curve ofthe teeth of the auxiliary feed dog.

From the above, it will be apparent that l have provided a feeding mechanism which is composed of comparatively few parts and wherein the two feed dogs arer both mounted at the free end of the feed bar. rllhese feed dogs are moved up and down with the fee-d bar, and all fabric engaging movements of the feed dogs are derived from the' endwise movement of a single feed bar extending lengthwise of the work supporting arm. lt will also be apparent that the auxiliary feed dog is given a differential movement through the aid of V controlling devices which shift the fulcrum of the auxiliary feed dog, and no actuating parts orvd'riving connections extend along the tubular arm except the single feed bar.

By shiftingv the connection between the link 18 and: the segment arm 20, the extent to which the fulcrum 19 of the auxiliary feed dog shifts is varied and' thereby the differential movements given to the auxiliary feed dog is' varied. The slot in the segment arm 20 is so shaped that, when this pivotal point of connection with the link 18 is at the extrem-e upper end of the slot, the fulcrum 19 moves tol the same extent as the feed bar and the auxiliary feed dog moves substantially in unison with the main feed dog, and as said pivotal connection is moved downwardly along the seg`A mental slot, the differential movement gradually increases.

It is obvious that minor changesv in the details of construction and the arrangement of the parts' may be made without departing from the spirit of the invention as set forth in the appended claims.

Having thus described the invention, what l claim as new and desire to secure by Letters-Patent is z- 1. A sewing machine including in combination, a cylindrical work supporting arm, a main feed dog located at the outer end of said work supporting arm, an auxiliary feed dog located at the outer end of said work supporting arm, a single driving connection extending along said work supporting arm for imparting feeding movements to both of said feed dogs, and means operatedlby said single driving connection for modifying the movements imparted to said auxiliary dog, whereby the extent of feeding movements imparted to the two feed dogs are different.

2. A sewing machine including in combination, a work supporting arm projecting away from the operator, a feeding mechanism for feeding the material being stitched off from the end of said arm including a main feed dog operating at the outer end of said work supporting arm, an auxiliary feed dog located adjacent the main feed dog and operating upon the material before it reaches the main feed dog, a single driving connection extending along said work supporting i arm forv imparting feeding lli() llO movements to both of the feed dogs, means for raising and lowering the feed dogs, and means located adjacent the outer end of the work supporting arm for modifying the feeding movements imparted to the auxiliary feed dog, whereby said feed dogs are given differential feeding movements.

8. A sewing machine including in combination, a work supporting arm projecting away from the operator, a f-eeding mechanism for feeding the material being stitched olf from the end of the arm includingy a feed bar extending lengthwise of the arm and having a main feed dog rigidly secured thereto, an auxiliary feed dog located adjacent the main feed dog and operating upon the material before it reaches the main feed dog, said auxiliary feed dog being pivoted to the main feed bar, means for raising and lowering the feed bar, and means operated by the main feed bar for modifying the movement imparted thereby to the auxiliary feed dog, whereby said feed dogs are given a differential movement.

4. A sewing machine including in combination, a work supporting arm, a feed bar extending lengthwise of saidy arm, means connected to the inner end of said feed bar for moving said feed bar back and forth, means for raising and lowering the forward end of the feed bar, a main feed dog rigidly carried by said feed bar, an auxiliary feed dog pivotally mounted on said feed bar adjacent the main feed dog, and a controlling means associated with the auxiliary feed dog for varying the amount of movement imparted to the auxiliary feed dog by said feed bar.

5. A sewing machine including in combination, a work supporting arm, a feed bar extending lengthwise of said arm, means connected to the inner end of said feed bar for moving said feed bar back and forth, means for raising and lowering the forward end 0f the feed bar, a main feed dog rigidly carried by said feed bar, an auxiliary feed dog pivotally mounted on said feed bar adjacent the main feed dog, and a controlling means associated with the auxiliary feed dog for varying the amount of movement imparted to the auxiliary feed dog by said feed bar, said controlling means including a shiftable fulcrum for said auxiliary feed dog, a swinging segmental arm, a link connecting said arm to the fulcrum for said auxiliary feed dog, and means whereby the connection between the link and the segmental arm may be shifted for varyingthe extent of movement of the fulcrum for said auxiliary feed dog.

6. A sewing machine including in combination, a work supporting arm, a feed bar extendin lengthwise of said arm, means connecte to the inner end of said feed bar for moving said feed bar back and forth,

means for raising and lowering the forward end of the feed bar, a main feed dog rigidly carried by said feed bar, an auxiliary feed dog pivotally mounted on said feed bar adjacent the main feed dog, and a controlling means associated with the auxiliary feed dog for varying the amount of movement imparted to the auxiliary feed dog by said feed bar, said controlling means including a shiftable fulcrum for said auxiliary feed dog, a swinging segmental arm, a link connecting said arm to the fulcrum for said auxiliary feed dog, and means whereby the connection between the link and the segmental arm may be shifted for varying the extent of movement of the fulcrum for said auxiliary feed dog, said shiftable connection between the link and the segmental arm being constructed so that said fulcrum may be shifted in timing with the movements of the feed bar and the auxiliary feed dog moved in unison with the main feed dog.

7. A sewing machine including in combination, a work supporting arm, a feed bar extending lengthwise of said arm, means connected to the inner end of said feed bar for moving said feed bar back and forth, means for raising and lowering the forward end of the feed bar, a main feed dog rigidly carried by said feed bar, an auxiliary feed dog pivotally mounted on said feed bar adjacent the main feed dog, and a controlling means associated with the auxiliary feed dog for varying the amount of movement imparted to the auxiliary feed dog by said feed bar, said controlling means including a pivoted segmental arm, a link connected to said arm and to said feed bar whereby the feed bar oscillates said arm, said arm having a segmental slot therein, a block shiftable in said slot, and a link connecting said block to the lower end of said auxiliary feed dog.

8. A sewing machine including in combination, a work supporting arm, a feed bar extending lengthwise of said arm, means connected to the inner end of said feed bar for moving said feed bar back and forth, means for raising and lowering the forward end of the feed bar, a main feed dog rigidly carried by said feed bar, an auxiliary feed dog pivotally mounted on said feed bar adjacent the main feed dog, and a controlling means associated with the auxiliary feed dog for varying the amount of movement imparted to the auxiliary feed dog by said feed bar, said controlling means including a pivoted segmental arm, a link connected to said arm and to said feed bar whereby the feed bar oscillates said arm, said arm having a segmental slot therein, a block shiftable in said slot, and a link connecting said block to the lower end of said auxiliary feed dog, and an adjusting screw having a ball headed socket connection with the segmental arm and a threaded connection With said block foiI shifting the block in said slot.

9. A sewing machine including in combination7 a Work supporting arm, a feed bar extending lengthwise of said arm, a main feed dog rigidly carried by said feed har, means for giving said feed bar back and forth and up and down movements, an auxiliary feed dog pivotally mounted on said feed bar adjacent the main feed dog, and a controlling means associated with the auxiliary feed dog for varying the amount of movement imparted to the auxiliary feed dog by said feed bar, said controlling means including a pivoted segmental arm a link connected to said arm and to said feed bar, a block shiftable on the segmental arm, adjusting means carried by the arm foi` shifting the block on the arm and holding said block in adjusted positions, and a link con* nected to the block and to the lower end of the auxiliary feed dog.

In testimony whereof, I aliix my signa ture.

SAMUEL GEORGE TATE. 

